Growth And Physiological Responses To Partial Root Zone Drying Irrigation In Populus Alba × P.glandulosa Cv.'84k' Clone

In this study,84K(Populus alba × P.glandulosa cv.‘84K')poplar was used as experimental material,indoor pot experiment,through saturated irrigation(CK),partial root zone drying irrigation(PRD)and deficit irrigation(DI)three kinds of water control treatment.The effects of partial root zone drying irrigation(PRD)on growth characteristics,photosynthetic characteristics,proline and relative water content of leaves of 84 K poplar were studied.At the same time,lable-free proteome technique and LC-MS metabolite technique were used to compare and analyze the effects of different treatments on the expression of differential proteins and differential metabolites,and the physiological mechanism and molecules of the effects of partial root zone drying irrigation on 84 K poplar were analyzed.The main conclusions are as follows:The main results are as follows:(1)Partial root zone drying irrigation can effectively promote the overall growth potential of 84 K poplar plants.In the process of treatment,the accumulation of plant height,ground stem,leaf number,internode number and biomass of 84 K poplar under root irrigation was higher than that of CK and DI.(2)The stomatal conductance and transpiration rate of photosynthetic parameters decreased with the decrease of irrigation water.the photosynthetic rate of root irrigation and control treatment was significantly higher than that of deficit irrigation,but there was no significant difference between root irrigation and control poplar.The chlorophyll content of poplar was higher than that of CK and DI under root irrigation,respectively.(3)A total of 3,733 proteins were identified in the proteome test,and the total number of peptides identified was 13,847.Among the PRD/CK comparison groups,a total of 238 differential proteins were screened,of which 59 were up-regulated and 179 were down-regulated,mainly in cells,cell membranes and organelles,which have catalytic and binding functions in the cellular processes and metabolic processes.In the DI/CK comparison group,194 differential proteins were screened,of which 50 were up-regulated and 63 were down-regulated.The anti-oxidative function of proteins and catalytic proteins in the cell membrane and organelle parts mainly perform metabolic and cellular signaling processes.(4)In the metabonomic test,244 significant differential metabolites(VIP>1,P<0.05)were screened in positive and negative ion mode.The differential metabolites mainly included amino acids,organic acids,sugars,purines and pyrimidines.84 K poplar adapts to local drought by enhancing the accumulation of TCA cycle and amino acid,while deficit irrigation adapts to external stress by increasing carbohydrate content and enhancing glucose metabolism.(5)In the results of the combined analysis of proteome and metabolome,it was concluded that root-irrigation significantly enriched the pyrimidine metabolic pathway and the purine metabolic pathway,and improved the plant's ability to resist stress.In general,Partial root-zone drying irrigation can increase the water absorption capacity by stimulating the absorption of roots on the saturated water supply side,and induce the signal transduction,protein synthesis,antioxidant enzymes and other related protein expression of the shoot tip of the plant and the rich metabolites such as organic acids,sugars,and purine.Set,improve the water use efficiency of plants,so as to achieve efficient water-saving cultivation of poplar.